This study is the continuation of the project initiated on April 1, 1979. The study deals with the phenomenon of genome alteration during animal development. Tetrahymena is chosen as the model system for this investigation. Two processes are being focused on in this study period: the amplification of ribosomal RNA gene and the elimination of specific DNA sequences. These sequences will be isolated from the germinal nucleus by using the DNA cloning techniques. The isolated sequences will be studied in full detail by sequencing and hybridization techniques. Special attention will be paid to any changes in sequence arrangement associated with amplification or elimination event. It is hoped that such studies will shed light on the mechanism of gene alteration in enlcaryotes.